Call a method when an object (specifically an object) is initialized

Question

I am making a mini state manager library for objects (because. don't ask.) and I want to use an approach like this (pseudo-code)

states = {}
when object is initialized {
if object.keys.states {
states[object.name] = object.keys.states;
}
}

/*
When object is initialized:
if object.keys.states exists:
states[object.name] = object.keys.states
*/

Is there a way to achieve this in typecript/javascript

Answer 1

is this typescript? if this is typescript you could use a class and an interface to execute that code or a constructor inside a class

  class states {
  states: State[] = [];
  constructor(statesc?: State[])
  {
      if (statesc) {
          for(var state in statesc)
          {
              //no need to do objects keys if you can rotate trough the given parameter
              //btw only a class constructor can be called when an object is instantiated otherwise you need to do the 
              //logic after it has been created
              this.states.push(statesc[state]);
          }
      }
  }
    
}

interface State{
    id: number;
    name: string;
}

//then you can do this
let states = new States(states); and the constructor gets called